Condition SO2 released / units before scrubbers 80 after scrubbers 12 A power station fits scrubbers to remove sulfur dioxide from its waste gases. The bar ...
Question 1 Report
| Condition | SO2 released / units |
|---|---|
| before scrubbers | 80 |
| after scrubbers | 12 |
A power station fits scrubbers to remove sulfur dioxide from its waste gases. The bar chart compares the sulfur dioxide released before and after fitting the scrubbers, and the table gives the values plotted. What is the best conclusion?
Answer Details
Compare the two figures for the same power station before and after the change. The sulfur dioxide released falls from 80 units to 12 units, and the bar on the chart drops to about a sixth of its original height. The removal is therefore \( \frac{80 - 12}{80} \times 100 = 85\% \), so the best conclusion is that the scrubbers greatly reduce the sulfur dioxide released.
The data directly contradict the claims that the release increases or stays the same, since the second bar is clearly much shorter. Nothing in the table or chart refers to carbon dioxide, so no conclusion about it can be drawn from this evidence. Scrubbers work by passing the waste gases through an alkaline slurry such as calcium oxide or calcium hydroxide, which neutralises the acidic sulfur dioxide.
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